Thermostatically operated electrical device



Aug. 23, 193%., E. KLAHN 1 THERMOSTATICALLY OPERATED ELECTRICAL DEVICE Original Filed July 26, 1926 2 Sheets-Sheet 1 Aug. 23, 1938. KLAHN 2,127,821

THERMOSTATICALLY OPERATED ELECTRICAL DEVICE Original Filed July 26, 1926 2 Sheets-Sheet 2 g5 Email-tome Patented Aug. 23, 1938 THERMOS'EATICALLY OPERATED ELEC- TRIBAL DEVIGE J Emil Klalm, New Vernon, N. J.; Johanna Margaret Percival administratrix of said Emil Klahn, deceased Original application July 26, 1926, Serial No. 124,917, now Patent No. 2,005,549, dated June 18, 1935. Divided and this application May 16, 1935, Serial No. 21,899

3 Claims. (Cl. 200-113) rise This invention relates to thermostatically operated switches and signalling apparatus operated thereby and has for its principal objects the provision of thermostatic switches which arecertain in operation, compact, durable and simple of construction, as well as the utilization of a thermostatic switch to intermittently operate a signalling apparatus. Further objects of the invention are the construction of a thermostatic switch without employing therein a iii-metallic thermostatic metal element. Various other objects and advantages are hereinafter specified.

My invention is fully set forth in the following description and drawings forming a part thereof, in which latter Figure l is an elevation of a unitary device comprising an electric light bulb and thermostatic switch;

Fig. 2 is an enlarged central vertical section partly in elevation of the device shown in Fig. 1;

Fig. 3 is a top plan view, partially cut away, of the construction shown in Fig. 2;

Fi 4 is a transverse section of a unitary device similar to that shown in Figs. 1 and 2, except that the same is providedwith a snapping thermostatic switch in lieu of the slow make and break switch mechanism shown in Figs. 1 and 3;

Fig. 5 is a plan view of a thermostatic switch wherein a snapping disc or membrane element is of itself heat-responsive and does'not require the employment of bi-metallic heat-responsive arms to actuate the snapping membrane element;

Fig. 6 is a vertical section partly in elevation of the construction shown in Fig. 5;

Fig. 7 is a diagrammatic view with a circuit diagram included therein of an arrangement whereby a single switch effects the alternate operation of three diiferent lights, the switch controlling the circuit through the heat-responsive arms being shown in a closed position; and

Fig. 8 is a similar view to that shown in Fig. '7,

except that the'switch is shown in a position to' correspond with the alternate position of the switch.

In the construction shown in Figs. 1 to 3, the heat of the lamp 50 is utilized directly to' operate the thermostatic switch, thus dispensing with the necessity for employing separate heating coils. This is accomplished by providing a flared hood 5| which is integral with the threaded metal sleeve 52 and is provided with insulation53 on its inner face in order to prevent short circuiting of a current flowing through the bi-metallic heatresponsive arms comprising an outer strip 54 of steel and an inner strip 55 of brass, the same being preferably rolled together to form an integral strip or membrane. As shown, one terminal of the filament 56, terminates in the sleeve 52 and the other filament 5'! terminates in a ring 58 anchored in the insulation base of thelamp and integral with a contact strip t9, which is provided. with a contact point 60 and which extends downwardly through the wall til of the insulation base and projects into the interior of the hood in such a position that its contact is adapted to serve as a stop and limit the inward movement of a contact 52 on-the inner face of one end of said bimetallicmembrane. Another contact strip 53 is integral with the metallic ring 63 on the end of said lamp and is also provided with a contact point as. through the wall ti of the base and projects into the interior of said hood in a position shown in Fig. 3, so that its contact point serves as a stop to prevent the further inward movement of the contact point 66. Said bi-metallic membrane is carried by said hood, but insulated therefrom by suitable insulation material 6'! as shown.

In the construction shown in Figs. 1 to 3, there is a slow make and break action between the contacts B0 and 62 on the one hand and 65 and 66 on the other. As is evident from the foregoing construction, when the lamp is threaded into a This contact strip 53 also extends socket, the current will be led into the bulb through the ring 84 and the contact strip 63, carrying the contact 65, thence through the bimetallic arm 55 to the contact points 62 and 60, thence through the contact 59 to the positive filament lead 51, thence through said filament and out through the negative filament lead 56 to the sleeve 52. As the lamp becomes heated, the temperature within the hood will be elevated by the radiation and conduction and the bi-metallic arms will expand, causing the separation of the contact 62 from the contact 60 on the one hand, and the contact 66 from 65 on the other. As these contacts are of precious metal, such as platinum or silver, the same will operate for long periods of time, without serious deterioration, on the ordinary electric circuit used for lighting purposes, such as for example, A. C. or D. C. Normally when the bi-metallic membrane is cold, its contacts will engage the contacts 60 and 65 on contact strips 59 and 83.

As shown in the construction illustrated in Figs. 1 to 3, the contacts 62 and 86 move in consonance with the bi-metallic arms of the split ring heat-responsive bi-metallic element. In Fig. 4 however, I have illustrated a. form of snapping thermostatic switch which is identical with that lie membrane element consists of an arcuate strip 68 of brass to which is riveted a similar arcuate strip 69 of steel in such a manner that the gap between the ends of the brass strip on the one hand is bridged by a strip or ribbon of steel and on the opposite side the gap between the ends of the steel strip is bridged by the brass strip, this latter member being secured to, but insulated from the hood 5| that corresponds to the hood 5i, except that said hood and its insulated lining 53' are indented to form a detent or boss member III which serves as a'stop to prevent the snapping portion ll of the steel bridge oi. the thermostatic arms from moving to a position beyond the critical or snapping zone whereby the moment the arms commence to cool and contract and there is insumcient pressure to hold the steel snapping element in contact with the stop 10, the former will instantly snap back into normal or cold position and engage the contacts 59" and 63' which likewise are positioned to serve as circuit closers and engage the snapping membrane when the same is just beyond or over the neutral line.

In the construction illustrated in Figs. 5 and 6 the snapping make and break action is accomplished without necessitating the employment of heat-responsive arms of bi-metallic or so-called thermostatic metal. In this construction an annular, inelastic frame 15 comprising a rigid ring of steel or other suitable material, is provided with a central rigid cross bar 16 of fibre or other suit-' able insulation material which is removably mounted thereon by means of screws 17, one of said screws serving as a negative binding post. Another adjustable binding post I8, provided with a locking nut 19, is threaded into the bar 18 and serves as a stop to limit the movement of a disc diaphragm 80, which latter is preferably formed of so-called hard or spring phosphor bronze and is seated on an annular shoulder Bl formed on the inner faceof said ring 15. An

- forming the tip of the stop 18,

annular sheet-metal ring 82 is snugly fitted between the top margin of said disc and projects to the level of the top of the ring 15, being retained in snug engagement with the diaphragm by the right adjustment of the cross-bar 16 against the upper edge thereof. The said diaphragm B0 is preformed, preferably by forcing the central area within the dotted circle shown in Fig. 5 upwardly enough to slightly stretch the same, whereby the diaphragm will normally tend to bulge upwardly and, if unobstructed by the stop 18, the center thereof would engage the center of the inner face of the bar 16. The contact 18' is adjusted so as to force the diaphragm downwardly into the posi tion shown in Fig. 6, so that the center thereof is but slightly above the neutral line designated by the letters NL. When heat is applied to the diaphragm, the same will almost immediately expand and, as it cannot bulge upwardly, the same suddenly snaps downwardly and assumes momentarily the position indicated by the lowest dot and dash line indicated in Fig. 6. Upon cooling again, the diaphragm will suddenly again snap, thus returning into engagement with the contact point If an electric current is supplied through the positive and negative binding posts 11 and 18, the same will be rapidly interrupted by the' aforesaid movement of the diaphragm upon alternate heating and cooling thereof, thus operating either a flashing signal, an electric motor or the like if desired, if the same is interposed in said circuit.

though the same will be 3,127,831 illustrated in Figs. 1 to 3, except that the bi-metal- If the light is positioned in s'ufilciently close proximity to the diaphragm, the heat of radiation from the light itself will, because of the sensitivity of the switch, serve to operate the same and alternately cause the abrupt make and break of the circuit therethrough. Such a switch is especially adapted for use in a chamber or receptacle as for example, a thermostat for controlling a domestic heating plant according to the temperature of a particular room selected as a standard or an incubator, electric oven, refrigerator or the like where it is desired to have the switch operate within a very small range of temperatures.

The employment of a diaphragm of phosphor bronze is especially desirable as not only does the same possess a high index of expansion which renders it highly sensitive to small variations of temperature, but it is capable of continued flexing or snapping movements without serious crystallization and fracture.

I a switch of the approximate dimension shown in Figs. 5 and 6, a phosphor bronze diaphragm .005" thick has been found to give excellent service.

In the modification shown in Figs. 7 and 8, the reference numerals 90, designate heat-- responsive arms of thermostatic metal having the steel element on the inner side and the brass element on the outside thereof, the same being mounted on a bracket member 9| and supporting a. steel snapping element 92 which is adapted to suddenly assume four different positions of rest. (see solid and dotted line positions in Figs. 7 and 8) during the slow movement of the thermostatic arms from their outermost to their innermost positions and vice versa.

A reciprocating rod or bar 93, provided with insulating sections 94, 94 is secured to said snapping element 9-2 adjacent the center thereof and the same is provided with knob shaped terminals 95, 95' which are adapted to co-operate with three pairs of Jaw members 86, 91 and 88 respectively. A switch, comprising jaws 99 and pivotal blade member Hill, the outer end of which is forked and has tines or arms l0! and I02 that are periodically tripped by a lug I03 carried by the rod 93, controls the heating circuit.

Aportion of the lighting circuit is caused to traverse the heating coils I04 of high resistance Nichrome wire or the like, which envelope the arms 90, 90' when the blade IN! is in engagement with the jaws 99 as it is also during the period when the rod 93 is in its first two positions of a cycle of movements as hereinafter described. Suitable adjustable stops I05, I 05' serve to limit the movement of said rod.

While I prefer to employ discs of hard or spring phosphor bronze, such as the disc 80 in the switches of the type shown in Figs. 5 and 6, nevertheless, other forms of snapping elements, such as flat or leaf springs of metal suitably preformed or deformed and anchored in rigid anchorages at the respective ends thereof may be employed, less sensitive than the membranes or discs and likewise spring brass and other metals capable of substitution therefor may be employed in lieu of phosphor bronze.

In the construction shown in Fig. 3, there is a slow separation of the contacts 60 from 62 and I8 from 86 respectively, but in the construction shown in Fig. 4, the steel bridge membrane ll snaps into and out of engagement with the twin or double contact members 58' and 63. As shown in this latter construction, the stop HI is so positioned that when the arms are heated, the spring 9,197,821 member II is prevented from moving substantially beyond the critical or snapping zone and consequently, on the slightest cooling of the thermostatic arms, which support such bridge mem- 5 her, beyond the point at which suflicient pressure is exerted to maintain the member II in intimate contact with its stop 10, the membrane II will snap out of engagement with the stop 10 and its contactpoints x, x will simultaneously 10 re-engage with the snapping action of the contact points 11, y on the strips 59' and 53' respectively. In this latter position the membrane mem-' brane is insuflicient to hold the membrane in contact with the contacts 3 y. s

In the construction shown in Figs. '7 and 8, the snapping element 92 is normally deformed so that it would naturally, if unconfined, assume the position indicated by the dot and dash line at the left of the three dot and dash lines shown in Fig. 7. Its first movement will result in the knob-shaped ends 95, 95' snapping into the next successive position so that the knob 95' is in engagement with the left-hand faces of the jaws 91 and knob 95 will assume its second position or the dot and dash line position shown-as the middle dot and dash line in Fig. 7. While in this position the current is still flowing through the switch 99 and the thermostatic arms will still continue to be heated by the coils I04. As the critical tempera-' the final dot and dash line position shown in Fig. 7, in which position the knob 95 will contact with the stop I05 and knob 95' will then be out of engagement with the jaws 91. The arm I02 of the bell crank lever will then be in the dot and dash line position. In this latter position of the switch, the flow of current through the supplemental switch 99 will be cut-off so that no current will be passing through the coils I09. The arms 90 will now immediately begin to cool and as soon as the pressure of the snapping element 92 is sufflcient, it will overcome the compression pressure of the jaws 98 and snap into the full line position shown in Fig. 8, wherein it will be noted 55 that the knob 95' engages the opposite face of the jaws 91 from that shown in the second position i. e. the left-handed'dot and dash line position of the knob shown in Fig. "I. In this position, the

stop I09 will have moved past the end of the arm I I92 and have just reached the arm IOI, but without moving the latter out of the position in which it was in when the knob 95 was in engagement with the stop I05. As the pressure of the snapping element 92 increases still, further, it will finally overcome the compression pressure of the laws 91 and the rod 99 will then-snap into the first position shown in Fig. 7 wherein the knob 95' was in engagement with the stop I05 and simultaneously with the moving ofthe knob the arm II 10 will be forced into the position shown in Fig. 7 by the impulse imparted thereto by the'stop I99 whereupon the current will be closed through the switch 99 so that the cycle of the heating of the coils I04 will again commence.

ture is reached, however, the rod 99 will snap into As is apparent from the foregoingdescription, the jaws 96, 91 and 99 are each adapted to normally exert either an effective grip upon the knobs 95, 95' as illustrated in Fig. 7 or to exert a sufllcient resistance to the knob 95' as illustrated in Fig. 8 to prevent the movement of the rod 93 until a sumcient pressure is built up by the snapping element 92 to result in the snapping action or movement of the rod 93 and its terminals into engagement with the next successive set of switch jaws, so that each movement will be a sudden and abrupt movement as distinguished from. a slow acting movement whereby serious arcing might otherwise occur.

The signal illustrated in Figs. 7 and s is peculiarly adaptable for street crossing wherein suc-. cessive fiashings of red, yellow or green signal lights is desired with the yellow being sov arranged. that it will flash between the alternate illumination of the red and green signals or at least in advance of the re-illumination of the red or green signals once the same has been extinguished.

The snapping element shown in Figs. 6 to 8 is preferably deformed by means of the deforming clamps, such as disclosed in my Patent NO.

1,784,450 the application for which was co-pending with this application or in any other desired manner, no claim being made herein to such deforming clamps as such.

This application is a division of an application No. 124,917, filed by me July 26, 1926, which matured into Patent No. 2,005,549 granted June 18, 1935.

Having thus described my invention, what I claim and desire to obtain by United States Letters Patent is;-

1. In a multi-circuit thermostatic switch, heat responsive means, a snapping element moving in one direction when said means is heated and in another direction when said means is cooled, a switching mechanism movable with said snapping element, switches spaced along the path of movement of said mechanism, to be operated when engaged thereby, said switches having friction means for frictionally engaging said mechresponsive means, a snapping element moving inone direction whensaid means is heated and in another direction when said means is cooled, a switching mechanism movable with said snapping element, at least three switches spaced along the path of movement of said mechanism, to be successively operated when engaged thereby, said switches having friction meansfor frictionally engaging said mechanism to resist movement thereof, said mechanism having friction meanscooperating with said switch friction means to restrain movement of said mechanism until sufiicient force is applied to said mechanism by said heat responsive means. 

